netdev - Re: [PATCH net-next v3 2/7] usbnet: smsc95xx: Don't clear read-only PHY interrupt

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Message-ID: <20220512115730.GA4703@wunner.de>
Date:   Thu, 12 May 2022 13:57:30 +0200
From:   Lukas Wunner <lukas@...ner.de>
To:     netdev@...r.kernel.org
Cc:     Andrew Lunn <andrew@...n.ch>
Subject: Re: [PATCH net-next v3 2/7] usbnet: smsc95xx: Don't clear read-only
 PHY interrupt

On Thu, May 12, 2022 at 10:42:02AM +0200, Lukas Wunner wrote:
> Upon receiving data from the Interrupt Endpoint, the SMSC LAN95xx driver
> attempts to clear the signaled interrupts by writing "all ones" to the
> Interrupt Status Register.
> 
> However the driver only ever enables a single type of interrupt, namely
> the PHY Interrupt.  And according to page 119 of the LAN950x datasheet,
> its bit in the Interrupt Status Register is read-only.  There's no other
> way to clear it than in a separate PHY register:
> 
> https://www.microchip.com/content/dam/mchp/documents/UNG/ProductDocuments/DataSheets/LAN950x-Data-Sheet-DS00001875D.pdf
> 
> Consequently, writing "all ones" to the Interrupt Status Register is
> pointless and can be dropped.
> 
> Tested-by: Oleksij Rempel <o.rempel@...gutronix.de> # LAN9514/9512/9500
> Tested-by: Ferry Toth <fntoth@...il.com> # LAN9514
> Signed-off-by: Lukas Wunner <lukas@...ner.de>

Reviewed-by: Andrew Lunn <andrew@...n.ch>

Forgot to add Andrew's R-b which he kindly provided here:
https://lore.kernel.org/netdev/YnGqtCDVHHpo%2FS+L@lunn.ch/

Let's see if patchwork picks the tag up if I add it like this.
My apologies for the inconvenience.